> ## Documentation Index
> Fetch the complete documentation index at: https://openfga.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Authorization Model Building Blocks

> Guides on the building blocks of authorization models in OpenFGA.

This section has guides that on the building blocks of authorization model.

<Note>
  **When to use**

  The content in this section is useful:

  * If you are starting with OpenFGA and want to learn the building blocks that can be used to build any model.
</Note>

<CardGroup>
  <Card title="Direct Relationships" href="/docs/modeling/building-blocks/direct-relationships">
    Learn to model relationships that may or may not be assigned directly to individual users.
  </Card>

  <Card title="Concentric Relationships" href="/docs/modeling/building-blocks/concentric-relationships">
    Learn to model nested relationships in your application.
  </Card>

  <Card title="Object to Object Relationships" href="/docs/modeling/building-blocks/object-to-object-relationships">
    Learn to model your application with objects that are not specifically tied to a user.
  </Card>

  <Card title="Usersets" href="/docs/modeling/building-blocks/usersets">
    Learn to model your application by assigning relationships to groups of users.
  </Card>
</CardGroup>